Line protection MCCB — 125 A, 4-pole, TM210 release
The Siemens 3VA1112-4GD42-0AA0 is a SENTRON molded case circuit breaker (MCCB) configured for line protection, rated 125 A continuous at 40 °C with a 4-pole design and a TM210 thermal-magnetic overcurrent release. It carries a 121 kA interrupting capacity at 240 V, stepping down to 75.6 kA at 415 V and 52.5 kA at 440 V — numbers that govern its fault-clearing capability in low-voltage distribution panels. The TM210 release means the thermal element tracks overloads (typically 1.05–1.3× In) while the magnetic instantaneous pickup is fixed at 10× In — a standard curve for feeder and main breaker duty where coordination with downstream branch breakers is the priority.
The 125 A rating holds flat from 40 °C through 50 °C, then derates to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. In a sealed, uncooled enclosure at 55 °C ambient, expect to lose 3 A of headroom — plan the load accordingly. Dimensions are 130 mm height, 101.6 mm width, 70 mm depth — a 4-pole footprint that fits standard Siemens SENTRON mounting bases. Maximum power loss is 28.1 W — a figure to include in the enclosure thermal budget, especially when multiple breakers are ganged in a row.
The N-conductor protection is designed at 100 % — full-rated neutral protection for 4-pole applications where the neutral carries the same current as the phases, typical in data-center or harmonic-rich loads.